A failure of an aircraft component during flight operations could lead to the grounding of an aircraft (AOG) until fault rectification is completed. This often results to high costs due to flight cancellations and delay propagation. With the technology of the digital twin, which is a virtual copy of a real aircraft, predictions of the technical reliability of aircraft components and thus the availability of the aircraft itself have recently become available. In the context of the combinatorial problem of aircraft resource planning, we examine how the predicted dispatch reliability of an aircraft could be used to achieve robustness of the schedule against AOG. We gain robustness only by flight scheduling, aircraft assignment and optimization of aircraft utilization, thus we avoid the use of expensive reserve ground times. We extend an integrated tail assignment and aircraft routing problem by ``dispatch reliability'' as a result from a digital twin. We disturb the flight schedule with random AOG cases, determine costs related to delay and flight cancellations, and improve robustness by taking into account the AOG-related costs in the objective function.